The purpose of this continuing project is the development and clinical implementation of a generalized system for external beam treatment planning. It will enable the optimum utilization of existing treatment facilities. The system is based on a generalized 3-D dose field model which covers photon and electron as well as neutron beams. The computer program and most of its clinical implementation was completed for the photon and electron fields available from the local 6 MV and 12 MV linear accelerators. The current capabilities include interactive simulation of most irradiation techniques, including the effect of most beam modifying devices. The transverse contours are overlaid on corresponding CT scans. Two of the four new radiation machines have been implemented for routine treatment planning. Work is progressing on implementation of a VAX-750 computer in conjunction with the PDP 11/70 system.